POLYMER PHYSICS AND STRUCTURE PROPERTY RELATIONSHIPS OF THERMALLY STABLE POLYARYLENE ETHERS FOR 2ND-ORDER NONLINEAR OPTICS/

This paper describes the structure/property relationships including th e polymer backbone structures and molecular weight, chromophore/polyme r interactions, and chromophore functionalization that influence the c hromophore orientational dynamics and polymer relaxations in a special class of thermally stable polymers that was recently developed for se cond-order nonlinear optical applications. These poly(arylene ether) p olymers (synthesis and characterization reported elsewhere) are being investigated because of their high glass transition temperatures (> 20 0 degrees C), which may minimize the randomization of chromophore orie ntation following electric field poling. They also have hydrogen-bondi ng sites that can interact with the chromophores, which may improve th e temporal stability of chromophore orientation following poling. Gene ralization of the observed polymer dynamics to other second-order nonl inear optical polymers is discussed. Second harmonic generation, a sec ond-order nonlinear optical effect, and dielectric relaxation are the two techniques employed to examine the intermolecular cooperativity an d segmental relaxation behavior in these polymers. By examination of t he second-order nonlinear optical properties of the doped or functiona lized polymeric material as a function of time and temperature and the dielectric relaxation phenomena as a function of frequency and temper ature, information concerning the local mobility and relaxation phenom ena of the polymer microenvironment surrounding the nonlinear optical chromophores can be obtained. The dielectric loss data were analyzed u sing the Havriliak-Negami empirical function and the Schonhals and Sch losser model to examine the extent of intermolecular coupling in these polymer systems. Results obtained using these two techniques are corr elated.